I have written a novel to Google about this. It took probably 6 emails before they understood what I was talking about. Now, they are aware of the issue but I doubt it will be fixed any time soon. This is because of 3 overarching issues:
.
I too reached out to Google.... and I too had to send at least 6 emails before someone actually bothered to read what I wrote instead of assuming I was talking about album art. I even attached multiple screenshots. Finally someone got it.
I'm not sure what the cause is, but from my conversations with them, it is not a matter of a lookup service. It is also, not a matter of them having the wrong artist image. According to google, the labels actually provide them with the artist images, and its not that their images are wrong, its that somewhere in google's coding, it is pulling in the wrong one from their database. Also, it is not limited to smaller or indy artists. I have seen problems with P Diddy artwork... and he's about as mainstream as it gets.
What I found is a few things that confirm this. If you go into the "music store" and search for an artist and go to that artist's "page", the images are all correct (at least for me). This means that the label has provided the correct image. However, I have seen the following two scenarios...
1. An 'incorrect artist' on your phone's app under my library, may be 'correct' in the desktop browser, and correct in the store. This tells me its coded wrong for the phone app.
2. An 'incorrect artist' on your phone's app under my library, may also be 'incorrect' in the desktop browser, but correct in the store. Obviously, that means it is coded wrong in both phone app and browser app.
Also, if artist imagery is not available, or is coded wrong and the app isn't pointing to imagery, the app defaults to an album cover with a blurred background of that album cover. Again, I've seen artists who have imagery in the store...show up in the app as an album cover. Obviously, these aren't coded right either.
One thing I've definitely noticed with ALOT of my incorrect artist imagery, is that they tend to be cases where there is just one song from one album, and the track title contains a "featuring another artist".
Anyway.... I've sent all this stuff to google with screenshots from the app, the browser and the store.... and they finally seemed to see what I was talking about. We'll see how it goes.